Guides · Updated 26 October 2026
French zoning letters U, AU, A and N: can you build on this plot?
In short
France’s local plans (plan local d’urbanisme, PLU) put every plot in one of four families. U is urban land with services in place, where building is allowed in principle. AU is land set aside for future development, sometimes only after the plan is amended. A (agricultural) and N (natural) zones allow little more than farm or forestry buildings and extensions to existing houses. Only a certificat d’urbanisme from the town hall gives an answer the council is bound by.
How to check the zoning of a plot
1. Find the plot
Search the address on the OpenParcels map and click the land. The sheet shows the cadastral reference (section and number) and the official area.
2. Read the zone
The sheet shows the zone code and label as published on the national planning portal, Géoportail de l’Urbanisme, with a link to the zone’s rules when the town provides one.
3. Open the zone’s rules
The written regulations say what is allowed, banned or allowed with conditions. Check the easement and risk maps too; they are annexes to the PLU.
4. Ask for a certificat d’urbanisme
It is free. The town hall replies within one month for an information certificate and two months for an operational one, which covers a specific project. It is valid for 18 months and can be extended by a year if the rules have not changed.
U: built-up areas
Article R151-18 of the French planning code (code de l’urbanisme) defines the U zone: areas that are already built up, or where existing or planned public services are enough to serve new buildings.
A U zone does not mean anything goes. The zone’s rules set the height, how far a building sits from the street and the neighbours, and how much of the plot can be covered. Easements or a natural-risk plan can add further limits.
AU: land for future development
Under article R151-20, AU zones are areas meant to be opened up for building. The code sets out two cases.
If the roads, water, power and drainage at the edge of the zone have enough capacity, building can go ahead as part of a planned development or as the internal services are put in. If they do not, the zone stays closed until the PLU is amended or revised. The town’s regulations say which case applies.
A: farmland
Article R151-22 lets a town zone land as A to protect its agricultural, biological or economic value, whether or not it has services.
Article R151-23 lists what may be allowed there: buildings needed for farming, and extensions, outbuildings and changes of use for existing buildings under articles L151-11 to L151-13. A new house with no link to a farm is not on the list.
N: natural areas and woodland
Article R151-24 allows an N zoning for one of five reasons: the quality of the landscape, commercial forestry, the area’s natural character, protecting natural resources, or preventing risks such as flooding.
Article R151-25 allows much the same as in A zones, plus forestry buildings.
The letters after the letter
Each town adds its own suffixes: UA, UB, 1AU, Ap, Nh. The law does not define them; the PLU’s written regulations do. In Arc-et-Senans (Doubs), Ap is farmland where new buildings are banned for landscape or ecological reasons.
Towns without a PLU may have a simpler carte communale, which only splits land into buildable and non-buildable sectors.
What OpenParcels shows
Three real plots on the map
Three plots a few kilometres apart near the Chaux forest in eastern France, each in a different family.
Arc-et-Senans (Doubs), plot A 764, 542 m². Zone UB, mixed fabric, mainly housing.
Open the plot →Arc-et-Senans (Doubs), plot ZK 119, 8,099 m². Zone Ap: farmland, no new buildings for landscape or ecological reasons.
Open the plot →Chissey-sur-Loue (Jura), plot AD 64, 32 ha. Zone N, natural and forest land; the plot sheet links to the rules.
Open the plot →
Frequently asked questions
Can I build a house on agricultural land (zone A) in France?
As a rule, no. Article R151-23 of the planning code only allows buildings needed for farming in zone A, plus extensions, outbuildings or changes of use for existing buildings under articles L151-11 to L151-13.
Is every plot in a U zone buildable?
No. U means the area is built up or served by utilities. The zone’s rules then set the conditions, and easements or a risk plan may apply. An operational certificat d’urbanisme answers for a specific project.
What is a certificat d’urbanisme and how long is it valid?
A free document from the town hall that states the planning rules for a plot, or whether a specific project is feasible. It is valid for 18 months and can be extended by one year if the rules, easements and taxes have not changed.
Where can I see a French town’s PLU?
On Géoportail de l’Urbanisme, the national portal for digitised planning documents, or at the town hall. OpenParcels reads this data and shows the zone on each plot’s sheet.
Sources
- Code de l'urbanisme, article R151-18 (zones U), Légifrance
- Code de l'urbanisme, article R151-20 (zones AU), Légifrance
- Code de l'urbanisme, article R151-22 (zones A), Légifrance
- Code de l'urbanisme, article R151-23 (constructions en zone A), Légifrance
- Code de l'urbanisme, article R151-24 (zones N), Légifrance
- Code de l'urbanisme, article R151-25 (constructions en zone N), Légifrance
- Certificat d'urbanisme, Service-Public.gouv.fr (vérifié le 2 juillet 2025)
- Géoportail de l'Urbanisme